Commitments and Contingencies - Future Minimum Rental Commitments (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Remaining 2019	$ 127
2020	30
Total cash payments remaining	157
Short-Term Lease
Lessee, Lease, Description [Line Items]
Remaining 2019	61
2020	0
Total cash payments remaining	61
ROU Lease
Lessee, Lease, Description [Line Items]
Remaining 2019	66
2020	30
Total cash payments remaining	$ 96